The present invention relates to bone grafting units and pertains particularly to improved combined cortical cancellous bone graft units and methods of making same.
The repair of bone defects is a problem that has plagued orthopedics for many decades. In particular, the bridging of bone defects is one of the most challenging of these problems. Such defects may occur as the result of traumatic extrusion, radial tumor resection and massive sequestration as a result of infection. Bone transplant for repairing or correcting defects of this type is an approach that has been practiced for many years with a limited degree of success.
Many approaches to the provision of transplant plugs or units for repair of bone defects have been proposed in recent years. However, many of these have not been particularly satisfactory for most applications.
Fresh autogenous bone is considered the most desirable grafting material for several reasons, including lack of immune response. However, this approach requires secondary surgery which may be too severe and traumatic for the patient. There are also cases wherein sufficient quantities of autogenous bone are not available. The best site from which to obtain certain bone graft material is the left posterior ilium of the patient. However, neither this nor any other source from a living patient can supply certain requirements.
Allograft materials from bone banks and from cadavers is the most practical source of bone grafting materials for most requirements. While this source has a number of drawbacks also, most of them can be overcome by processing and preservation techniques.
One of the most desirable requirements of grafting material is that it be integrated into the adjacent bone or skeleton structure as quickly as possible. The spongy cancellous bone provides the most suitable matrix for rapid bone regeneration and repair. The relative loose structure of cancellous bone permits rapid and usually complete revascularization. This makes it most suitable for bone regeneration.
Another major requirement of most bone transplants is that it have strength and support capability. Cortical bone has high strength and is suitable for support structures. However, cortical bone revascularizes through preexisting periphery, but the process is rather slow and incomplete.
The applicant has devised a combination structure that provides both of these desirable qualities. This structure is a combined cortical cancellous bone graft unit.